1. The Field of the Invention
The present invention relates to bag assemblies and heat exchanger systems that incorporate the bag assemblies.
2. The Relevant Technology
Bioreactors are used in the growth of cells and microorganisms. Conventional bioreactors comprise a rigid tank that can be sealed closed. A drive shaft with propeller is rotatably disposed within the tank. The propeller functions to suspend and mix the culture. A sparger is mounted on the bottom of the tank and is used to deliver gas to the culture to control the oxygen content and pH of the culture.
Great care must be taken to sterilize and maintain the sterility of the bioreactor so that the culture does not become contaminated. Accordingly, between the production of different batches of cultures, the mixing tank, mixer, and all other reusable components that contact the culture must be carefully cleaned to avoid any cross contamination. The cleaning of the structural components is labor intensive, time consuming, and costly. For example, the cleaning can require the use of chemical cleaners such as sodium hydroxide and may require steam sterilization as well. The use of chemical cleaners has the additional challenge of being relatively dangerous to use and cleaning agents can be difficult and/or expensive to dispose of once used.
In addition to being labor intensive to clean, conventional bioreactors have operational shortcoming. For example, as a result of need for sparging the culture within the container, gas collects at the upper end of the container. To maintain the system within a desired operating pressure, a portion of the gas must be periodically or continuously removed without jeopardizing the sterility of the system. This is typically accomplished by venting the gas out through a filter. However, such filters can often become temporarily plugged as a result of moisture from the gas condensing within the filter.